According to The NPD Group’s Weekly Retail Tracking Service, unit sales of portable power packs designed to charge mobile devices such as smartphones and tablets, have grown 101 percent during the two week period between July 10 and July 23 compared to the year prior. While product promotions played a role in the sales increases experienced within the category, it was the extraordinary popularity of the mobile video game, Pokémon Go, that drove the most demand over this time period.

Demand for portable power packs has been strong this year, with unit sales increasing 35 percent year-over-year for the 12 months ending June 2016. More recently, though, sales growth for the devices has slowed. In the six weeks leading up to Pokémon Go’s launch, unit sales were just four percent above the same period a year ago. However, in the two weeks since the game launched, sales of portable power packs reached nearly 1.2 million units, representing a marked increase in sales growth.

“Pokémon Go is the summer’s hottest game partly because it utilizes features like location, motion sensors and augmented reality in your smartphone- however, these features consume more of the phone’s battery life,” said Ben Arnold, executive director, industry analyst for consumer technology at The NPD Group. “As a way to compensate for the extra battery usage, consumers are buying portable power packs so they can continue to play, uninterrupted.”